Mycoplasma spp. is currently known the tiniest bacteria capable of self-replication outside host cells. Although swine enzootic pneumonia would not cause swine death, it will reduce feeding efficiency and cause growth retardation, inflammation, and immunosuppression as well as make swine more vulnerable to infection of other pathogens, which therefore become economic damage of the industry.
So far, swine enzootic pneumonia is prevented by three major strategies, including: medicine administration, environment management, and vaccination. Seeing the bad prevention efficiency of antibiotics to Mycoplasma hyopneumoniae, medicine administration can only used for treatment purposes and is hard to meet prevention needs. Furthermore, considering that drug abuse may lead to a larger infection causing by drug-resistant bacteria, medicine administration needs cautious plans and exists a lot of limitations.
Environment management forms the basis of prevention of Mycoplasma spp. infection. Good piggery sanitation and management would be helpful to reduce occurrence of infection. On the other hand, prevention could be more comprehensive through vaccination.
The conventional vaccines in the field use inactive/dead bacteria as the active ingredient thereof. However, the price of the conventional vaccines is too high because Mycoplasma spp. is fastidious bacteria and is difficult to be cultured in the laboratory. In order to reduce the cost of Mycoplasma spp. vaccines, scientists continuously try to develop vaccines of different types, such as: (1) attenuated vaccines, (2) vector vaccines, (3) subunit vaccines, and (4) DNA vaccines. Among them, subunit vaccines show the most potential because the advantages of ease in production and high safety.
To date, there are several potential candidate proteins that could be used for M. hyopneumoniae vaccines; however, there is no further report verifying the proteins suitable for M. hyopneumoniae vaccines.